List all attributions here, this include "self-attributions":

Astronaut reused from workbook 06
    Attribution goes to the course for providing the OBJ

Houses resued from workbook 08
Car reused from workbook 08
Tree reused from workbook 08

Planet's water procedural texture found online
    https://shaderfrog.com/app/view/6610

Moon texture found online
    https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4720

Space skybox found online
    https://opengameart.org/content/ulukais-space-skyboxes